wifi: rtw89: fix long RX latency in low power mode

In low power mode, regular IO is power off, so we don't schedule napi to
poll RX and TX completion. Therefore, calling ieee80211_rx_napi() with
napi instance causes long RX latency. To fix this, use NULL as argument,
and then it can use netif_receive_skb_list() to receive.
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20220610072610.27095-10-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/core.c

@@ -1483,11 +1483,17 @@ static void rtw89_core_rx_to_mac80211(struct rtw89_dev *rtwdev,
 				      struct sk_buff *skb_ppdu,
 				      struct ieee80211_rx_status *rx_status)
 {
+	struct napi_struct *napi = &rtwdev->napi;
+
+	/* In low power mode, napi isn't scheduled. Receive it to netif. */
+	if (unlikely(!test_bit(NAPI_STATE_SCHED, &napi->state)))
+		napi = NULL;
+
 	rtw89_core_hw_to_sband_rate(rx_status);
 	rtw89_core_rx_stats(rtwdev, phy_ppdu, desc_info, skb_ppdu);
 	/* In low power mode, it does RX in thread context. */
 	local_bh_disable();
-	ieee80211_rx_napi(rtwdev->hw, NULL, skb_ppdu, &rtwdev->napi);
+	ieee80211_rx_napi(rtwdev->hw, NULL, skb_ppdu, napi);
 	local_bh_enable();
 	rtwdev->napi_budget_countdown--;
 }